Systems and methods for managing the trajectory of an aircraft must meet demanding operational safety conditions.
In particular, RNP-AR type aerial operations are demanding. The required navigation performance (RNP) may be authorisation required (AR). RNP designates procedures that have been created to specify the conditions to be met as regards airspace and its use. RNP-AR procedures are able to provide significant benefits in terms of use and safety relative to other surface navigation procedures (RNAV) by prescribing an enhanced navigation functionality, integrity and precision so as to enable operations using smaller minimal obstacle clearances, which make it possible to implement approach and departure procedures in situations where the application of other procedures is not realisable or acceptable from the operational point of view.
For example in such an RNP-AR context, regulations require the aircraft to be kept in a corridor of 2×RNP around the reference trajectory in case of what is called a remote fault (with a fault probability comprised between 10^-5 and 10^-7 per operation).
In particular, in the configuration of a conventional dual system (two independent navigation chains),a fault in one of the chains (or “sides”) of the system—implying the undesired modification of the trajectory to which the aircraft is slaved—must be able to be detected and above all isolated in order to continue the flight on the side without fault.
Patent document US2012/0092193 entitled “Method And Device For Aiding The Managing Of Air Operations With Required Navigation And Guidance Performance” discloses a method and device for assisting with the conduct of aerial operations requiring a guarantee of navigation performance and guidance in an RNP-AR context. The disclosure requires the use of N systems, N being an integer higher than or equal to 3. Approaches involving triplex architectures have limitations.
Other known existing approaches involve the use of TAWS or manual means for crosschecking monitoring means. These approaches also have limitations.
There is a need for advanced methods and systems especially allowing operational safety requirements to be covered, especially in an RNP-AR context.